Is it just me or is Potion master absolutely useless. Healing potions sell for nothing on most servers. Why would anyone choose it over flask/transmute?

It was awesome in TBC when the potion CD wasn't affected by combat. I would regularly use 2 to 5 per pull in most raid fights. Even engineers made profit from mana injectors, which allowed potions to stack to 20 (they only stacked to 5 until Cata I think). Though back then, it wasn't even about healing potions, it was about temp stat boosts for the DPS and tanks, while healers went through mana pots. When Wrath hit, mana stopped being an issue for healers, so the cost of those went down, while stat boost pots were less valuable as only one per fight could be used.

Basically, potion mastery's usefulness got nerfed hard after the one xpac it was introduced.

It was awesome in TBC when the potion CD wasn't affected by combat. I would regularly use 2 to 5 per pull in most raid fights. Even engineers made profit from mana injectors, which allowed potions to stack to 20 (they only stacked to 5 until Cata I think). Though back then, it wasn't even about healing potions, it was about temp stat boosts for the DPS and tanks, while healers went through mana pots. When Wrath hit, mana stopped being an issue for healers, so the cost of those went down, while stat boost pots were less valuable as only one per fight could be used.

Basically, potion mastery's usefulness got nerfed hard after the one xpac it was introduced.

yeah. one pot per combat is one of the more stupid moves that they made.